Biology subjects

Lewinson, O.

Publications and source records attributed to Lewinson, O..

6 recordsLinked to original sources

bioRxiv2026

Transition Metal-Weak Organic Acid Synergy Enables Rapid Bactericidal and sporicidal Activity

The global rise in antibiotic-resistant bacteria underscores the urgent need for alternative antimicrobial strategies capable of limiting bacterial growth and viability. We previously demonstrated that weak organic acids and transition metals combine synergistically to strongly inhibit bacterial growth. Here, we extend these findings to determine whether this interaction results only in bacteriostatic suppression or can induce irreversible killing. Using standardized quantitative assays, selected acid-metal combinations achieved rapid bactericidal activity, producing >5-log reductions in Gram-negative and Gram-positive bacterial load after brief exposure at concentrations substantially lower than those required for many conventional disinfectants. This activity extended beyond vegetative cells. Bacillus cereus spores, used as a surrogate for spores of Bacillus anthracis, exhibited significant loss of viability under defined conditions. Given the environmental persistence of anthrax spores and their relevance in biological threat scenarios, these findings have implications not only for antimicrobial resistance mitigation but also for biodefense and environmental decontamination. Sporicidal efficacy was exposure dependent, with prolonged contact enabling effective killing at reduced concentrations. Together, these results establish acid-metal systems as scalable antimicrobial agents with bactericidal and sporicidal activity relevant to public health and global security. Importance statementAntibiotic resistance and the persistence of bacterial spores demand new antimicrobial strategies that are both effective and practical. This study shows that combining weak organic acids with transition metals transforms two modest antimicrobial agents into a powerful broad-spectrum killing system. These synergistic formulations rapidly eradicate Gram-negative and Gram-positive bacteria, achieving bactericidal activity at concentrations substantially lower than those used in many conventional disinfectants. Importantly, their activity extends to bacterial spores, among the most resilient biological structures known and a major challenge in environmental decontamination and biodefense. Using Bacillus cereus as a surrogate for Bacillus anthracis, we demonstrate dramatic sporicidal activity, reducing spore viability by up to six orders of magnitude. By coupling strong efficacy with a simple, scalable, and potentially environmentally compatible formulation, this work establishes transition metal-organic acid combinations as a promising new platform for infection control, environmental decontamination, and biodefense preparedness.

microbiology↗

bioRxiv2025

Prokaryotic mechanosensitive channels mediate copper influx

Copper is an essential micronutrient in all kingdoms of life, requiring a meticulous balance between acquisition and toxic overload. While copper import in eukaryotes has been investigated extensively, few prokaryotic copper importers have been identified, leading to the notion that cytoplasmic copper uptake is unnecessary in prokaryotes. Here we report that mechanosensitive channels are key players in prokaryotic copper import. Deletion of the gene encoding the E. coli small mechanosensitive channel, EcMscS, leads to significantly reduced copper influx. Conversely, overexpression of EcMscS leads to increased copper influx, elevated intracellular copper content, and renders cells hypersensitive to copper. Furthermore, specific channel blockers and competing permeating ions inhibit EcMscS copper conductance, lowering intracellular copper accumulation and alleviating copper hypersensitivity. These findings extend beyond E. coli, as other prokaryotic small mechanosensitive channels of bacterial and archaeal origin also facilitate copper influx. Taken together, these results uncover a previously unknown moonlighting function for mechanosensitive channels as a pathway for prokaryotic copper uptake.

microbiology↗

bioRxiv2025

When Less is MORE: Counterintuitive Stoichiometries and Cellular Abundances are Essential for ABC transporters function

Prokaryotes acquire essential nutrients primarily through ABC importers, consisting of an ATPase, a permease, and a substrate-binding protein. These importers are highly underrepresented in proteomic databases, limiting our knowledge about their cellular copy numbers, component stoichiometry, and the mechanistic implications of these parameters. We developed a tailored proteomic approach to compile the most comprehensive dataset to date of the E. coli ABC importome. Functional assays and analysis of deletion strains revealed novel mechanistic features, linking molecular mechanisms to cellular abundances, co-localization, and component stoichiometries. We observed 4-5 orders of magnitude variation in import system abundances, with copy numbers tuned to nutrient hierarchies essential for growth. Abundances of substrate-binding proteins are unrelated to their substrate binding affinities but are tightly, yet inversely, correlated with their interaction affinity with permeases. Counterintuitive component stoichiometries are crucial for function, offering insights into the design principles of multi-component protein systems, potentially extending beyond ABC importers. TeaserBacterias nutrient absorption secrets unveiled: deciphering the complexity of ABC transporter systems required for optimal growth.

biochemistry↗

bioRxiv2023

Computational analysis of long-range allosteric communications in CFTR

Malfunction of the CFTR protein results in cystic fibrosis, one of the most common hereditary diseases. CFTR functions as an anion channel, the gating of which is controlled by long- range allosteric communications. Allostery also has direct bearings on CF treatment: the most effective CFTR drugs modulate its activity allosterically. Herein, we integrated Gaussian Network Model, Transfer Entropy, and Anisotropic Normal Mode-Langevin dynamics and investigated the allosteric communications network of CFTR. The results are in remarkable agreement with experimental observations and mutational analysis and provide extensive novel insight. We identified residues that serve as pivotal allosteric sources and transducers, many of which correspond to disease causing mutations. We find that in the ATP-free form, dynamic fluctuations of the residues that comprise the ATP binding sites facilitate the initial binding of the nucleotide. Subsequent binding of ATP then brings to the fore and focuses dynamic fluctuations that were present in a latent and diffuse form in the absence of ATP. We demonstrate that drugs that potentiate CFTRs conductance do so not by directly acting on the gating residues, but rather by mimicking the allosteric signal sent by the ATP binding sites. We have also uncovered a previously undiscovered allosteric "hotspot" located proximal to the docking site of the phosphorylated Regulatory (R) domain, thereby establishing a molecular foundation for its phosphorylation- dependent excitatory role. This study unveils the molecular underpinnings of allosteric connectivity within CFTR and highlights a novel allosteric "hotspot" that could serve as a promising target for the development of novel therapeutic interventions.

biophysics↗

bioRxiv2022

Initiation of fibronectin fibrillogenesis is an enzyme-dependent process

Fibronectin fibrillogenesis and mechanosensing both depend on integrin-mediated force transmission to the extracellular-matrix. However, force transmission is in itself dependent on fibrillogenesis, and fibronectin fibrils are found in soft embryos where high forces cannot be applied, suggesting that force cannot be the sole initiator of fibrillogenesis. Here we identify a nucleation step prior to force transmission, driven by fibronectin oxidation mediated by lysyl-oxidase enzyme family members. This oxidation induces fibronectin clustering that promotes early adhesion, alters cellular response to soft matrices, and enhances force transmission to the matrix. In contrast, absence of fibronectin oxidation abrogates fibrillogenesis, perturbs cell-matrix adhesion, and compromises mechanosensation. Moreover, fibronectin oxidation promotes cancer cells colony formation in soft agar as well as collective and single-cell migration. These results reveal a force-independent enzyme-dependent mechanism that initiates fibronectin fibrillogenesis, establishing a critical step in cell adhesion and mechanosensing.

cell biology↗

bioRxiv2021

Listeria monocytogenes TcyKLMN cystine/cysteine transporter facilitates glutathione synthesis and virulence gene expression

Listeria monocytogenes (Lm) is a saprophyte and a human intracellular pathogen. Upon invasion into mammalian cells, it senses multiple metabolic and environmental signals that collectively trigger its transition to the pathogenic state. One of these signals is the tripeptide glutathione, which acts as an allosteric activator of Lms master virulence regulator, PrfA. While glutathione synthesis by Lm was shown to be critical for PrfA activation and virulence gene expression, it remains unclear how this tripeptide is synthesized under changing environments, especially in light of the observation that Lm is auxotrophic to one of its precursors, cysteine. Here, we show that the ABC transporter TcyKLMN is a cystine/cysteine importer that supplies cysteine for glutathione synthesis, hence mediating the induction of the virulence genes. Further, we demonstrate that this transporter is negatively regulated by three metabolic regulators: CodY, CymR and CysK, which sense and respond to changing concentrations of branched chain amino acids (BCAA) and cysteine. The data indicate that under low concentrations of BCAA, TcyKLMN is up-regulated, driving the production of glutathione by supplying cysteine, thereby facilitating PrfA activation. These findings provide molecular insight into the coupling of Lm metabolism and virulence, connecting BCAA sensing to cysteine uptake and glutathione biosynthesis, as a mechanism that controls virulence gene expression. This study exemplifies how bacterial pathogens sense their intracellular environment and exploit essential metabolites as effectors of virulence. ImportanceBacterial pathogens sense the repertoire of metabolites in the mammalian niche and use this information to shift into a pathogenic state to accomplish successful infection. Glutathione is a virulence-activating signal that is synthesized by L. monocytogenes during infection of mammalian cells. In this study, we show that cysteine uptake via TcyKLMN drives glutathione synthesis and virulence gene expression. The data emphasize the intimate cross-regulation between metabolism and virulence in bacterial pathogens.

microbiology↗